I hear a lot of talk in the autism community about self-stimulatory behavior, known colloquially and in shorthand as “Stims” or “Stimming.” For the most part, the self-advocates have convinced most people that stimming is good, it relieves stress/helps focus, and that autists should be allowed to stim. This is good, but I would like to go further than that and say that everyone stims.
Yes, that's right. I did, in fact, say everyone stims. Don't believe me? Think of a time to when someone was nervous or impatient. Did they rap their fingers? That's a stim. Did they tap their foot? Stim. Play with their hair? Yes, that's a stim too. Even things like whistling could be a stim. The point is, everyone does it to some extent; the only reason autistic stims seem so unusual is that our versions are different.
There is also of course the seemingly unusual sources and frequencies of the need to stim, but those are due to our hypersensitivity to sensory stimuli and changes. A lot of the non-autistic world is foreign to us, and therefore we have a higher level of anxiety when dealing with said world. I have a certain degree of confidence that were I to pluck a non-autist from their home country and put them in a foreign land, they would be stimming much more than they do at home.
“But Cisco, people look at my child strange when he stims!” Does the child notice? If the child does not notice, then perhaps a re-evaluation of exactly why this bothers you is in order. Likewise if the child notices but values the joy stimming brings over the strange looks they receive. Now, granted, extenuating circumstances do apply to this: If the kid is flailing their arms about in the knife section of a store or in a museum, there are practical concerns there.
Still, if you must control a child's stimming for whatever reason, I would suggest evaluating the stims and channeling them into one or both of two paths: Either find a hobby or skill that utilizes this behavior and encourage them to pursue that, or find an “accepted” stim similar to what the child is actually doing and see if that relieves them in a similar manner.